1. Field of the Invention
The present invention relates to display apparatus and display method, and it particularly relates to a technique which reduces the unevenness and dispersion of luminance by smoothing a deterioration of respective optical elements in an active matrix display screen.
2. Description of the Related Art
Organic electroluminescent display apparatus (hereinafter referred to also as “organic EL apparatus” or “organic EL panel”) is attracting much attention as new flat type display apparatus. In particular, active-matrix type organic EL display apparatus including thin film transistors (hereinafter referred to also as “TFT”) as switching elements is the most promising candidate for the next generation display apparatus to replace the currently widely prevailing liquid crystal display (LCD) apparatus, and is a subject of intensive research and development activities competing for putting it to practical use.
Unlike the liquid crystal display elements, the organic EL elements themselves emit light. Thus, the backlight which is an indispensable structure in the liquid crystal display apparatus is no longer required, so that it is expected that the apparatus will be made further thinner and lighter. Utilizing the property of self-luminance, it is expected that the organic EL elements will be used as light emitting devices such as backlight of LCD apparatus.
It is a well-known fact that the organic EL elements deteriorate with luminescence and the luminance thereof drops gradually. When the same image is displayed for many hours in the same region, the deterioration in the organic EL element having high-luminance pixels deteriorates faster than that having low-luminance pixels, in accordance with luminance distribution of an image in question. As a result, even during the time when the image is not displayed at all, the dispersion or the irregularity of luminance corresponding to this image is visibly observed. Namely, the so-called screen burn-in phenomenon occurs. Even if the respective organic EL elements have enough life duration, the difficulties are encountered in their usage if the burn-in occurs in the panels. Thus, in order to provide long-life organic EL panels with high display quality, it is of course important to develop organic luminescent material resistant to deterioration, but it is also extremely important to develop a technology that suppresses the occurrence of luminance disparity and screen burn-in phenomenon.